The present invention relates to a new and improved construction of circuit for detecting disturbances in travel of a yarn, thread, filament or the like -- hereinafter simply usually referred to as yarn -- at a textile machine, comprising a probe delivering an electrical signal in the presence of such disturbances, the probe being coupled by means of discriminator stages at a pre-selection counter structured for setting the maximum permissible number of disturbances and also connected with a multivibrator which, upon exceeding the aforesaid number, delivers a disturbance signal.